Scientists can’t tie any single weather event to climate change, but they can assess how it has altered the odds of such events happening, Tom Peterson of the National Oceanic and Atmospheric Administration told reporters.

In the Texas case, researchers at Oregon State University and in England noted that the state suffered through record heat last year. It happened during a La Niña weather pattern. Caused by dropping temperatures of the central Pacific Ocean, La Niña generally cools the world but would be expected to make the southern United States warmer than usual.

Global warming has made such a Texas heat wave about 20 times more likely to happen during a La Niña year, researchers found.

Scientists from Oxford University and the British government looked at temperatures in central England. Last November was the second-warmest in that region in more than 300 years. Their analysis concluded that global warming has made such a warm November about 62 times more likely.

A third analysis considered unusually severe river flooding last year in central and southern Thailand. It found no sign that climate change played a role in that event, noting that the amount of rainfall was not very unusual. The scale of the flooding was influenced more by factors like reservoir operation policies, researchers wrote.